/** * date : 2026-09-19 14:14:02 * author : Nyaan */ #define NDEBUG #include #pragma GCC optimize("O3,unroll-loops") #pragma GCC target("avx2") using namespace std; // intrinstic #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // utility namespace Nyaan { using ll = long long; using i64 = long long; using u64 = unsigned long long; using i128 = __int128_t; using u128 = __uint128_t; template using V = vector; template using VV = vector>; using vi = vector; using vl = vector; using vd = V; using vs = V; using vvi = vector>; using vvl = vector>; template using minpq = priority_queue, greater>; template struct P : pair { template constexpr P(Args... args) : pair(args...) {} using pair::first; using pair::second; P &operator+=(const P &r) { first += r.first; second += r.second; return *this; } P &operator-=(const P &r) { first -= r.first; second -= r.second; return *this; } P &operator*=(const P &r) { first *= r.first; second *= r.second; return *this; } template P &operator*=(const S &r) { first *= r, second *= r; return *this; } P operator+(const P &r) const { return P(*this) += r; } P operator-(const P &r) const { return P(*this) -= r; } P operator*(const P &r) const { return P(*this) *= r; } template P operator*(const S &r) const { return P(*this) *= r; } P operator-() const { return P{-first, -second}; } }; using pl = P; using pi = P; using vp = V; constexpr int inf = 1001001001; constexpr long long infLL = 4004004004004004004LL; template int sz(const T &t) { return t.size(); } template inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; } template inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; } template inline T Max(const vector &v) { return *max_element(begin(v), end(v)); } template inline T Min(const vector &v) { return *min_element(begin(v), end(v)); } template inline long long Sum(const vector &v) { return accumulate(begin(v), end(v), 0LL); } template int lb(const vector &v, const T &a) { return lower_bound(begin(v), end(v), a) - begin(v); } template int ub(const vector &v, const T &a) { return upper_bound(begin(v), end(v), a) - begin(v); } constexpr long long TEN(int n) { unsigned long long ret = 1, x = 10; for (; n; x *= x, n >>= 1) ret *= (n & 1 ? x : 1); return ret; } template pair mkp(const T &t, const U &u) { return make_pair(t, u); } template vector mkrui(const vector &v, bool rev = false) { vector ret(v.size() + 1); if (rev) { for (int i = int(v.size()) - 1; i >= 0; i--) ret[i] = v[i] + ret[i + 1]; } else { for (int i = 0; i < int(v.size()); i++) ret[i + 1] = ret[i] + v[i]; } return ret; }; template vector mkuni(const vector &v) { vector ret(v); sort(ret.begin(), ret.end()); ret.erase(unique(ret.begin(), ret.end()), ret.end()); return ret; } template vector mkord(int N, F f) { vector ord(N); iota(begin(ord), end(ord), 0); sort(begin(ord), end(ord), f); return ord; } template vector mkinv(vector &v) { int max_val = *max_element(begin(v), end(v)); vector inv(max_val + 1, -1); for (int i = 0; i < (int)v.size(); i++) inv[v[i]] = i; return inv; } vector mkiota(int n) { vector ret(n); iota(begin(ret), end(ret), 0); return ret; } template T mkrev(const T &v) { T w{v}; reverse(begin(w), end(w)); return w; } template bool nxp(T &v) { return next_permutation(begin(v), end(v)); } // 返り値の型は入力の T に依存 // i 要素目 : [0, a[i]) template vector> product(const vector &a) { vector> ret; vector v; auto dfs = [&](auto rc, int i) -> void { if (i == (int)a.size()) { ret.push_back(v); return; } for (int j = 0; j < a[i]; j++) v.push_back(j), rc(rc, i + 1), v.pop_back(); }; dfs(dfs, 0); return ret; } // F : function(void(T&)), mod を取る操作 // T : 整数型のときはオーバーフローに注意する template T Power(T a, long long n, const T &I, const function &f) { T res = I; for (; n; f(a = a * a), n >>= 1) { if (n & 1) f(res = res * a); } return res; } // T : 整数型のときはオーバーフローに注意する template T Power(T a, long long n, const T &I = T{1}) { return Power(a, n, I, function{[](T &) -> void {}}); } template T Rev(const T &v) { T res = v; reverse(begin(res), end(res)); return res; } template vector Transpose(const vector &v) { using U = typename T::value_type; if(v.empty()) return {}; int H = v.size(), W = v[0].size(); vector res(W, T(H, U{})); for (int i = 0; i < H; i++) { for (int j = 0; j < W; j++) { res[j][i] = v[i][j]; } } return res; } template vector Rotate(const vector &v, int clockwise = true) { using U = typename T::value_type; int H = v.size(), W = v[0].size(); vector res(W, T(H, U{})); for (int i = 0; i < H; i++) { for (int j = 0; j < W; j++) { if (clockwise) { res[W - 1 - j][i] = v[i][j]; } else { res[j][H - 1 - i] = v[i][j]; } } } return res; } } // namespace Nyaan // bit operation namespace Nyaan { __attribute__((target("popcnt"))) inline int popcnt(const u64 &a) { return __builtin_popcountll(a); } inline int lsb(const u64 &a) { return a ? __builtin_ctzll(a) : 64; } inline int ctz(const u64 &a) { return a ? __builtin_ctzll(a) : 64; } inline int msb(const u64 &a) { return a ? 63 - __builtin_clzll(a) : -1; } template inline int gbit(const T &a, int i) { return (a >> i) & 1; } template inline void sbit(T &a, int i, bool b) { if (gbit(a, i) != b) a ^= T(1) << i; } constexpr long long PW(int n) { return 1LL << n; } constexpr long long MSK(int n) { return (1LL << n) - 1; } } // namespace Nyaan // inout namespace Nyaan { template ostream &operator<<(ostream &os, const pair &p) { os << p.first << " " << p.second; return os; } template istream &operator>>(istream &is, pair &p) { is >> p.first >> p.second; return is; } template ostream &operator<<(ostream &os, const vector &v) { int s = (int)v.size(); for (int i = 0; i < s; i++) os << (i ? " " : "") << v[i]; return os; } template istream &operator>>(istream &is, vector &v) { for (auto &x : v) is >> x; return is; } istream &operator>>(istream &is, __int128_t &x) { string S; is >> S; x = 0; int flag = 0; for (auto &c : S) { if (c == '-') { flag = true; continue; } x *= 10; x += c - '0'; } if (flag) x = -x; return is; } istream &operator>>(istream &is, __uint128_t &x) { string S; is >> S; x = 0; for (auto &c : S) { x *= 10; x += c - '0'; } return is; } ostream &operator<<(ostream &os, __int128_t x) { if (x == 0) return os << 0; if (x < 0) os << '-', x = -x; string S; while (x) S.push_back('0' + x % 10), x /= 10; reverse(begin(S), end(S)); return os << S; } ostream &operator<<(ostream &os, __uint128_t x) { if (x == 0) return os << 0; string S; while (x) S.push_back('0' + x % 10), x /= 10; reverse(begin(S), end(S)); return os << S; } void in() {} template void in(T &t, U &...u) { cin >> t; in(u...); } void out() { cout << "\n"; } template void out(const T &t, const U &...u) { cout << t; if (sizeof...(u)) cout << sep; out(u...); } struct IoSetupNya { IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7); } } iosetupnya; } // namespace Nyaan // debug #ifdef NyaanDebug #define trc(...) (void(0)) #else #define trc(...) (void(0)) #endif #ifdef NyaanLocal #define trc2(...) (void(0)) #else #define trc2(...) (void(0)) #endif // macro #define each(x, v) for (auto&& x : v) #define each2(x, y, v) for (auto&& [x, y] : v) #define all(v) (v).begin(), (v).end() #define rep(i, N) for (long long i = 0; i < (long long)(N); i++) #define repr(i, N) for (long long i = (long long)(N)-1; i >= 0; i--) #define rep1(i, N) for (long long i = 1; i <= (long long)(N); i++) #define repr1(i, N) for (long long i = (N); (long long)(i) > 0; i--) #define reg(i, a, b) for (long long i = (a); i < (b); i++) #define regr(i, a, b) for (long long i = (b)-1; i >= (a); i--) #define fi first #define se second #define ini(...) \ int __VA_ARGS__; \ in(__VA_ARGS__) #define inl(...) \ long long __VA_ARGS__; \ in(__VA_ARGS__) #define ins(...) \ string __VA_ARGS__; \ in(__VA_ARGS__) #define in2(s, t) \ for (int i = 0; i < (int)s.size(); i++) { \ in(s[i], t[i]); \ } #define in3(s, t, u) \ for (int i = 0; i < (int)s.size(); i++) { \ in(s[i], t[i], u[i]); \ } #define in4(s, t, u, v) \ for (int i = 0; i < (int)s.size(); i++) { \ in(s[i], t[i], u[i], v[i]); \ } #define die(...) \ do { \ Nyaan::out(__VA_ARGS__); \ return; \ } while (0) namespace Nyaan { void solve(); } int main() { Nyaan::solve(); } using namespace std; namespace internal { unsigned long long non_deterministic_seed() { unsigned long long m = chrono::duration_cast( chrono::high_resolution_clock::now().time_since_epoch()) .count(); m ^= 9845834732710364265uLL; m ^= m << 24, m ^= m >> 31, m ^= m << 35; return m; } unsigned long long deterministic_seed() { return 88172645463325252UL; } // 64 bit の seed 値を生成 (手元では seed 固定) // 連続で呼び出すと同じ値が何度も返ってくるので注意 // #define RANDOMIZED_SEED するとシードがランダムになる unsigned long long seed() { #if defined(DETERMINISTIC_SEED) return deterministic_seed(); #elif defined(NyaanLocal) && !defined(RANDOMIZED_SEED) return deterministic_seed(); #else return non_deterministic_seed(); #endif } } // namespace internal namespace my_rand { using i64 = long long; using u64 = unsigned long long; // [0, 2^64 - 1) u64 rng() { static u64 _x = internal::seed(); return _x ^= _x << 7, _x ^= _x >> 9; } // [l, r] i64 rng(i64 l, i64 r) { assert(l <= r); return l + rng() % u64(r - l + 1); } // [l, r) i64 randint(i64 l, i64 r) { assert(l < r); return l + rng() % u64(r - l); } // choose n numbers from [l, r) without overlapping vector randset(i64 l, i64 r, i64 n) { assert(l <= r && n <= r - l); unordered_set s; for (i64 i = n; i; --i) { i64 m = randint(l, r + 1 - i); if (s.find(m) != s.end()) m = r - i; s.insert(m); } vector ret; for (auto& x : s) ret.push_back(x); sort(begin(ret), end(ret)); return ret; } // [0.0, 1.0) double rnd() { return rng() * 5.42101086242752217004e-20; } // [l, r) double rnd(double l, double r) { assert(l < r); return l + rnd() * (r - l); } template void randshf(vector& v) { int n = v.size(); for (int i = 1; i < n; i++) swap(v[i], v[randint(0, i + 1)]); } } // namespace my_rand using my_rand::randint; using my_rand::randset; using my_rand::randshf; using my_rand::rnd; using my_rand::rng; using namespace std; struct Timer { chrono::high_resolution_clock::time_point st; Timer() { reset(); } void reset() { st = chrono::high_resolution_clock::now(); } long long elapsed() { auto ed = chrono::high_resolution_clock::now(); return chrono::duration_cast(ed - st).count(); } long long operator()() { return elapsed(); } }; // using namespace Nyaan; namespace miscalc { #define vc vector template using vvc = vc>; template using vvvc = vc>>; #define overload4(_1, _2, _3, _4, name, ...) name #define repi1(i, n) for (int i = 0, nnnnn = int(n); i < nnnnn; i++) #define repi2(i, l, r) for (int i = int(l), rrrrr = int(r); i < rrrrr; i++) #define repi3(i, l, r, d) \ for (int i = int(l), rrrrr = int(r), ddddd = int(d); \ ddddd > 0 ? i < rrrrr : i > rrrrr; i += d) #define repi(...) overload4(__VA_ARGS__, repi3, repi2, repi1)(__VA_ARGS__) #define eb emplace_back template inline T SZ(const V& x) { return x.size(); } template struct MatrixMod2 : vc> { using M = MatrixMod2; using V = bitset; using vc>::vector; using vc>::operator=; using vc>::size; int m; MatrixMod2(int n, int m, int diag = 0, int non_diag = 0) : m(m) { assert(m <= (int)MAX_M); this->resize(n); repi(i, n) repi(j, m)(*this)[i][j] = i == j ? diag : non_diag; } template MatrixMod2(const vvc& vec) { const int n = vec.size(); m = n == 0 ? 0 : vec[0].size(); assert(m <= (int)MAX_M); this->resize(n); repi(i, n) { assert(SZ(vec[i]) == m); repi(j, m) { assert(vec[i][j] == T(0) || vec[i][j] == T(1)); (*this)[i][j] = vec[i][j]; } } } MatrixMod2(const vc& vec) { const int n = vec.size(); m = n == 0 ? 0 : vec[0].size(); assert(m <= (int)MAX_M); this->resize(n); repi(i, n) { assert(SZ(vec[i]) == m); repi(j, m) { assert(vec[i][j] == '0' || vec[i][j] == '1'); (*this)[i][j] = vec[i][j] - '0'; } } } template vvc to_vvi() const { const int n = size(); vvc res(n, vc(m)); repi(i, n) repi(j, m) res[i][j] = (*this)[i][j]; return res; } vc to_vstr() const { const int n = size(); vc res(n, string(m, '0')); repi(i, n) repi(j, m) res[i][j] += (*this)[i][j]; return res; } M operator-() const { return *this; } // 加算・減算 O(nm/w) M& operator+=(const M& b) { const int n = size(); repi(i, n)(*this)[i] ^= b[i]; return *this; } M& operator-=(const M& b) { return *this += b; } M operator+(const M& b) const { return M(*this) += b; } M operator-(const M& b) const { return M(*this) -= b; } // 乗算 O(nmk/w) template MatrixMod2 operator*(const MatrixMod2& b) const { const int n = size(), m_ = b.size(), k = b.m; assert(m == m_); MatrixMod2 res(n, k); repi(i, n) { auto row = (*this)[i]; for (int j = row._Find_first(); j < m; j = row._Find_next(j)) res[i] ^= b[j]; } return res; } template MatrixMod2 operator*=(const MatrixMod2& b) { return *this = *this * b; } // 正方行列 // O(n^3 log k / w) template M pow(T k) const { const int n = size(); assert(n == m); M res(1), tmp(*this); while (k > 0) { if (k & 1) res *= tmp; tmp *= tmp; k >>= 1; } return res; } // rref が true の場合、簡約行列にしたものを返す // rref が false の場合、階段行列にしたものを返す // O(nm min(n, m) / w) M row_reduction(bool rref = false) const { const int n = size(); M a(*this); for (int i = 0, j = 0; i < n && j < m; j++) { repi(k, i, n) { if (a[k][j]) { swap(a[i], a[k]); break; } } if (a[i][j] == 0) continue; if (rref) repi(k, i) if (a[k][j]) a[k] ^= a[i]; repi(k, i + 1, n) if (a[k][j]) a[k] ^= a[i]; i++; } return a; } // O(nm min(n, m) / w) template I rank() const { const int n = size(); M a = row_reduction(); I res = 0; repi(i, n) if (a[i] != 0) res++; return res; } // 正方行列、O(n^3/w) template I det() const { const int n = size(); assert(n == m); M a = row_reduction(); I res = 1; repi(i, n) res &= a[i][i]; return res; } // 正方行列、O(n^3/w) // (存在するか, 存在する場合逆行列) pair inv() const { const int n = size(); assert(n == m); MatrixMod2 a(n, 2 * n); repi(i, n) repi(j, n) a[i][j] = (*this)[i][j]; repi(i, n) a[i][n + i] = 1; auto b = a.row_reduction(true); repi(i, n) if (b[i][i] == 0) return {false, {}}; M res(n, n); repi(i, n) repi(j, n) res[i][j] = b[i][n + j]; return {true, res}; } // (解が存在するか, 解のひとつ, 基底) // O(nm min(n, m) / w + m^2 template tuple> solve(const bitset& b) const { const int n = size(); assert(n <= (int)MAX_N); MatrixMod2 a(n, m + 1); repi(i, n) rep(j, m) a[i][j] = (*this)[i][j]; repi(i, n) a[i][m] = b[i]; a = a.row_reduction(true); int rk = 0; repi(i, n) if (a[i] != 0) rk++; V sol; vc basis; vc piv(m, -1); for (int i = 0, j = 0; i < rk; i++) { while (j < m && a[i][j] == 0) j++; if (j == m) return {false, {}, {}}; sol[j] = a[i][m], piv[j] = i; } repi(j, m) { if (piv[j] != -1) continue; V ba; ba[j] = 1; repi(k, j) if (piv[k] != -1) ba[k] = a[piv[k]][j]; basis.eb(ba); } return {true, sol, basis}; } }; } // namespace miscalc void q() { ini(N); V S(N); in(S); vvi A(N, vi(N)); rep(i, N) rep(j, N) A[i][j] = S[i][j] == '#' ? 1 : 0; set> ans; auto flip_square = [&](int k, int r, int c) { V res; reg(i, -k, k + 1) { res.emplace_back(r + i, c + i); if (i != 0) res.emplace_back(r + i, c - i); } return res; }; auto add = [&](int k, int r, int c) { each2(i, j, flip_square(k, r, c)) A[i][j] ^= 1; if (ans.count({k, r + 1, c + 1})) { ans.erase({k, r + 1, c + 1}); } else { ans.insert({k, r + 1, c + 1}); } }; vp kouho; rep(i, N) rep(j, N) { if (i < 2 or j < 2 or i + 2 >= N or j + 2 >= N) kouho.emplace_back(i, j); } int C = sz(kouho); trc2(C); auto pos = [&](int i, int j) { auto k = lb(kouho, pl{i, j}); if (k == sz(kouho) or kouho[k] != pl{i, j}) return -1; return k; }; // 外周 2x2 で掃き出し constexpr int X = 12032; using bs = bitset; V M(C); each(b, M) b.reset(); V> sousa; for (int k : {1, 2, 3}) { reg(r, k, N - k) reg(c, k, N - k) { bs b; b.reset(); auto f = flip_square(k, r, c); int exist = 0; each2(i, j, f) exist |= pos(i, j) != -1; if (!exist) continue; each2(i, j, f) { int p = pos(i, j); if (p != -1) M[p].set(sz(sousa)); } sousa.emplace_back(k, r, c); if (sz(sousa) >= X) exit(1); } } int D = sz(sousa); trc2(D); miscalc::MatrixMod2 MM(C, D); rep(i, C) rep(j, D) if (M[i][j]) MM[i].set(j); bitset bb; bb.reset(); rep(c, C) { auto [i, j] = kouho[c]; if (A[i][j]) bb.set(c); } auto [flag, sol, basis] = MM.solve(bb); if (!flag) die(-1); rep(d, D) if (sol[d]) { auto [k, r, c] = sousa[d]; add(k, r, c); } rep(i, N) rep(j, N) { if (A[i][j]) { assert(2 <= i and i + 2 < N); assert(2 <= j and j + 2 < N); add(1, i - 1, j - 1); add(1, i - 1, j + 1); add(1, i + 1, j - 1); add(1, i + 1, j + 1); add(2, i, j); } } out(sz(ans)); for (auto& [k, r, c] : ans) out(k, r, c); } void test() {} void Nyaan::solve() { #ifdef NyaanLocal // test(); trc2("test OK"); #endif Timer timer; int t = 1; // in(t); while (t--) q(); trc2(timer()); }